TEHRAN, Iran â€” Iran's semiofficial Mehr News Agency says three explosions have hit gas pipelines near the country's holy city of Qom, in the same area where simultaneous blasts took place two months ago.

The lines carry gas from Iran's gas refineries in the south to the country's northwest.

The report says Friday's explosions cut the gas flow through those lines but power plants switched to oil for electricity production.

Mehr says an investigation is under way as to what caused the blasts.

In February, officials said the blasts were not caused by technical failures but did not say if they were acts of sabotage.

Iran's oil and gas sector has been hit by an increasing number of attacks recently but authorities have provided no explanation for them.